I changed tires first and bought aftermarket sensors. I didn't like this tool, thought about returning it, but didn't know anything about the tpms tool or the sensor. I recommend if you buy sensors make sure you wake them up and activate them in your car. You might need a better tool for that. So I couldn't get this tool to communicate the new sensors to the car, but little did I know that I bought fake frequency sensors after I found out I used this tool to clear the TPMS gauge and it works like a charm. I highly recommend this tool or maybe even better updated ones that can do more